The pathogenesis of asthma remains uncertain although a variety of factors including immune mechanisms, learning, and emotions have been shown to be of importance in the development and/or perpetuation of the illness. The principal focus of the proposed studies involves the role of emotional factors and conditioning in mediating airway obstruction in asthma. A conditioning model of asthma is developed. This model suggests that cues associated with emotional responses (known to occur during acute asthma episodes) become conditioned stimuli for airway obstruction as an inevitable result of repeated asthma attacks. According to the model, systematic desensitization and deep skeletal relaxation training should be effective modes of treatment in asthma by reducing one component of the stimulus-response chain leading to airway obstruction. One objective, therefore, is a thorough evaluation of systematic desensitization and relaxation training as modes of treatment in asthma. In addition, an attempt is made to evaluate the immediate effects of manipulations of the emotional response on the airway calibre of asthmatics.